Vectronics VEC-412K - Manual (Page 27)

VEC-412K Owner's Manual Rapid Battery Charger/Conditioner Kit
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Charger Pending(trickle charge) OFF for 1.375 sec and ON for 0.125 sec
Fast Charge ON continuous
Discharge Cycle ON for 1.375 sec and OFF for 0.125 sec
Charge complete and Top-Off ON for 0.125 sec, OFF for 0.125 sec
Table 4.
The status of the controller is shown by the state of CR1, the red Status LED.
Determining Full Charge: For NiCd batteries, three methods of determining
full charge are used: Maximum Voltage Determination Method, Time-Out, and a
Negative Increment of Voltage Detection Method. The fast charging rate will
cease if any of one of these three conditions are meet.
The Negative Increment of Voltage Detection Method will not work on NiMH
battery packs. During fast charge NiMH battery packs are monitored for
maximum pack voltage, and the charging time is also limited by the Time Out
setting.
Maximum Voltage Determination Method: When the battery pack reaches
1.82 volts-per-cell the charger concludes the fast charge cycle and enters the Top
Off charging mode.
Time Out: See Table 3. When setting the Fast Charge Rate, a Time-Out setting
is also determined. This is a fail-safe safety feature that prevents overcharging.
If for some reason the battery fails the Voltage Determination Method or the
Negative Increment of Voltage Detection Method for determining full charge,
the Time-Out timer will end the fast charge cycle before battery damage occurs.
The Time-Out timer allows sufficient time for a pack to reach a fully charged
condition, unless defective.
Getting the Best Charge: NiCad battery capacity is reduced at very low or
high temperatures. Do not charge batteries that are very warm or cold. Let
batteries stabilize at room temperature before charging. Allow batteries a
cooling off period between multiple charge/discharge memory cleansing cycles.
Determining Battery Capacity: Time how long it takes to fully discharge a
charged battery pack. Multiply the number of hours by the discharge rate to
find the mAh capacity of the battery. For example, a battery takes 2.3 hours to
discharge at the 240 mA discharge setting. 2.3 hours x 240 mA = 552 mAh
(battery capacity C). Note: for best accuracy, use mA meter in series with the
battery to find the exact discharge current.
Battery Failure: With proper care it is not unusual for NiCad battery packs to
last 3, 4 or 5 years. Internal shorts often occur in older battery cells, or cells